in my physics homework I have this question in about voltage. It says "Four point charges equal in magnitude are arranged at the corners of a square as shown in the figure. What is the magnitude of the electric potential at points a, b, and c? I know the answer is that it zero everywhere but I do not understand why, can somebody explain?
Each point a, b, c is equidistant from pairs of equal +ve and -ve charges. In each equidistant pair the potentials due to the +ve and -ve charges have the same magnitude but opposite sign, so their sum is zero.